/*  touchmon.c    touch sensor with loop monitor    requires "turtle.c"*/    int     LEFT_TOUCH=     14;int     RIGHT_TOUCH=    15;/* ID of avoid process */int avoid_pid;void main(){    avoid_pid= start_process(avoid());    start_process(monitor());}void avoid(){    while (1) {        forward();                if (digital(LEFT_TOUCH)) {            backward();            sleep(.25);            right();            sleep(.4);        }                if (digital(RIGHT_TOUCH)) {            backward();            sleep(.25);            left();            sleep(.4);        }    }}